Improve compatibility with distutils proper logging

setuptools/logging.py

@@ -22,13 +22,13 @@ def configure():
     handlers = err_handler, out_handler
     logging.basicConfig(
         format="{message}", style='{', handlers=handlers, level=logging.DEBUG)
-    monkey.patch_func(set_threshold, distutils.log, 'set_threshold')
-
-    # For some reason `distutils.log` module is getting cached in `distutils.dist`
-    # and then loaded again when patched,
-    # implying: id(distutils.log) != id(distutils.dist.log).
-    # Make sure the same module object is used everywhere:
-    distutils.dist.log = distutils.log
+    if hasattr(distutils.log, 'Log'):
+        monkey.patch_func(set_threshold, distutils.log, 'set_threshold')
+        # For some reason `distutils.log` module is getting cached in `distutils.dist`
+        # and then loaded again when patched,
+        # implying: id(distutils.log) != id(distutils.dist.log).
+        # Make sure the same module object is used everywhere:
+        distutils.dist.log = distutils.log
 
 
 def set_threshold(level):

setuptools/tests/test_build_ext.py

@@ -194,16 +194,26 @@ def get_build_ext_cmd(self, optional: bool, **opts):
         cmd.ensure_finalized()
         return cmd
 
-    def test_optional(self, tmpdir_cwd, capsys):
+    def get_log_messages(self, caplog, capsys):
+        """
+        Historically, distutils "logged" by printing to sys.std*.
+        Later versions adopted the logging framework. Grab
+        messages regardless of how they were captured.
+        """
+        std = capsys.readouterr()
+        return std.out.splitlines() + std.err.splitlines() + caplog.messages
+
+    def test_optional(self, tmpdir_cwd, caplog, capsys):
         """
         If optional extensions fail to build, setuptools should show the error
         in the logs but not fail to build
         """
         cmd = self.get_build_ext_cmd(optional=True, inplace=True)
         cmd.run()
-        logs = capsys.readouterr()
-        messages = (logs.out + logs.err)
-        assert 'build_ext: building extension "spam.eggs" failed' in messages
+        assert any(
+            'build_ext: building extension "spam.eggs" failed'
+            for msg in self.get_log_messages(caplog, capsys)
+        )
         # No compile error exception should be raised
 
     def test_non_optional(self, tmpdir_cwd):

setuptools/tests/test_distutils_adoption.py

@@ -138,14 +138,11 @@ def test_modules_are_not_duplicated_on_import(
 
 
 ENSURE_LOG_IMPORT_IS_NOT_DUPLICATED = r"""
-# Similar to ENSURE_IMPORTS_ARE_NOT_DUPLICATED
+import types
 import distutils.dist as dist
 from distutils import log
-
-assert dist.log == log, (
-    f"\n{dist.log}\n!=\n{log}"
-)
-
+if isinstance(dist.log, types.ModuleType):
+    assert dist.log == log, f"\n{dist.log}\n!=\n{log}"
 print("success")
 """
 

setuptools/tests/test_manifest.py

@@ -322,6 +322,8 @@ class TestFileListTest(TempDirTestCase):
     """
 
     def setup_method(self, method):
+        if not hasattr(log, 'Log'):
+            pytest.skip("These tests rely on old logging infra")
         super(TestFileListTest, self).setup_method(method)
         self.threshold = log.set_threshold(log.FATAL)
         self._old_log = log.Log._log